Avila Shows Progress in Covalent Cancer Drugs at Prominent ASH Confab

Boston-based Avila Therapeutics announced data today from early human trials of its lead cancer drug, AVL-292, which the company is presenting at the American Society of Hematology (ASH) annual meeting in San Diego. The results support the company’s plans to move the drug into more extensive Phase 2 trials next year, says CEO Katrine Bosley.

Avila specializes in developing “covalent” drugs, which are molecules designed to bind so tightly to disease-causing proteins that they shut down that protein’s activity for a prolonged period of time. AVL-292 specifically inhibits an enzyme called Bruton’s tyrosine kinase (Btk), which has been implicated in so-called B cell cancers, such as chronic lymphocytic leukemia. “Folks have understood the biology of Btk and been interested in it for a long time,” Bosley says. “I think you’ll see a lot of excitement around Btk at ASH.”

Bosley hopes some of that excitement will be generated by Avila’s study. The data showed that five out of six patients with chronic lymphocytic leukemia who received AVL-292 remained stable, meaning their disease did not progress. Those patients have stayed on the drug for more than 100 days since the start of the trial. Blood tests showed that at the largest of the two doses tested, AVL-292 inhibited Btk over the long run.

Bosley says one of the greatest challenges in targeting Btk has been to design drugs that could block it without affecting healthy processes in the body. “That’s what was hard—making drugs that were specificenough to Btk,” she says. “Covalent small molecules form a permanent, irreversible bond with the target and they do it with great specificity.”

Avila plans to start the second arm of the Phase 1 study in the first quarter of next year, and Bosley says it will involve about 70 patients. She says the company will share its specific plans for the Phase 2 study in either the first or the second quarter.

Avila is also studying the potential of AVL-292 to prevent bone destruction in patients suffering from multiple myeloma. During the ASH conference, the company presented data from animal trials showing that the drug seems to inhibit the function of osteoclasts—a type of cell that breaks down bone.

But AVL-292 is Avila’s most advanced program—and one that it has kept full rights to, at least so far. The Leukemia & Lymphoma Society is providing up to $3.2 million to support the development, in a partnership announced in March 2010, but the agreement does not require Avila to share any portion of future proceeds from the drug with the society.

Bosley says taking on a partner for AVL-292 isn’t out of the question, but it also isn’t necessary right now. “For us it’s all about the best way to enhance the program,” she says. “If we thought [a partner] would be a valuable path forward we would consider that.”